It is a common practice to attach so-called "crowder wheels" onto the front end of a round baler so that, as the baler moves along the windrow, wide portions of the windrow which might otherwise lie outside of the baler's pickup mechanism are gathered inwardly far enough to be lined up with the baler. See, for example, U.S. Pat. Nos. 3,678,669; 4,182,103; 4,214,429; and 4,446,685.
Such crowder wheels present a number of problems, however. For one thing, they must be mounted on the baler in such a manner that they are far enough ahead of the pickup to engage the hay and complete its transferring movement inwardly by the time the pickup comes along and engages the transferred hay. They must also be mounted in oblique, angled relationship to the path of progress of the machine so as to deflect the crop inwardly, and at the same time, they must be made rotatable so that when the ground is engaged they can simply spin in a free-wheeling rather than shove the earth and materials along like a bulldozer or snow plow. It is also necessary that the wheels be able to swing up and down independently of the baler to yield for rocks and variations in ground contour as the baler moves along, all of which leads to some less than ideal mounting arrangements in order to accommodate these needs.
Moreover, since the crowder wheels are circular, they present a relatively small effective crop engaging area adjacent their lower portions at any one point in time. Although the wheels can be increased in diameter and thus increase the surface area that is in contact with the crop materials for better control, there are normally space limitations that prevent the wheels from exceeding a certain maximum diameter. Sometimes, when the baler is going slow or heavy crop conditions are encountered, the crowder wheels barely rotate. Yet, this is precisely the time when the converging action may be needed the most to move the materials into the path of the pickup.